Apparatus has heretofore been marketed by applicants' assignee for use as a training aid in theory and operation of hydromechanical fluid power systems. In such apparatus, a plurality of hydromechanical devices, such as fluid-powered hydraulic motors, valves and cylinders, are mounted on a vertical panel carried by a wheeled frame. A hydraulic pump is carried by the frame, and is selectively connectable by quick-disconnect hoses to one or more of the hydromechanical devices. All components are standard industrial devices with which the laboratory or classroom trainee thus becomes familiar through a series of exercises or problems set by an instructor or instruction manual. For training in electrohydraulics, which represents the current trend in the fluid power industry, an electrohydraulic servo trainer module has been provided as a separate unit or as an accessory to the standard hydromechanical trainer.
U.S. Pat. No. 5,009,067 assigned to the assignee hereof discloses apparatus for training an operator in theory and practice of electrohydraulic control systems. The apparatus includes a plurality of electrohydraulic devices for performing hydraulic operations as differing functions of associated electronic control signals. A plurality of differing electronic controllers are adapted to generate electronic control signals to operate the electrohydraulic devices. The electronic controllers bear graphic indicia identifying the controller and associating each controller with corresponding electrohydraulic devices on the training unit. Each controller has a plurality of available input, output and control connections, which may be selectively interconnected with each other and with the electrohydraulic devices by suitable cables for configuring the controller and associated device in a multiplicity of differing operating modes. The electrohydraulic devices are connectable by quick-disconnect hoses to a fluid power source carried by the trainer, and are associated with indicia for generating a visually observable indication of operation of the devices, so that an operator can observe effects of differing electronic control configurations on the devices.
Although the apparatus described above and disclosed in the noted patent have met with substantial acceptance and success in both the academic and the industrial training environments, further improvements remain desirable. In particular, in order to obtain complete training in both hydromechanical and electrohydraulic fluid power systems, the training centers must have at least one training apparatus of each type. The hydraulic load devices in the prior art, such as the rotary hydraulic motors and linear motors or actuators, are not dynamically loaded, so that operation during training is not as realistic as desired. It is therefore a general object of the present invention to provide a fluid power training apparatus of the described character that is more versatile in terms of capability for training a student or technician in a wide variety of fluid power control techniques, that forms an integral unit with which the trainee can readily become familiar, and in which the electronic control modules are constructed and arranged realistically to simulate situations that the trainee may encounter in the field while at the same time providing enhanced trainee understanding of electronic control theory and practice.